Depth profiling by SIMS—depth resolution, dynamic range and sensitivity

Abstract

Abstract Depth profiling by secondary ion mass spectrometry is described with emphasis on three important aspects: (1) depth resolution, (2) dynamic range and (3) sensitivity. It is shown how, for samples which do not roughen during sputtering, depth resolution is limited by atomic mixing effects and the flatness of the analyzed area. The dynamic range of depth profiles is shown to be limited by (a) crater edge effects, (b) neutral beam effects and (c) several types of instrumental background. These include mass spectral overlap, residual gas contamination, redeposition and ‘memory’ effects, and detection of unfilterable particles. In the absence of measurable background, sensitivity is shown to be related to analyzed area and depth resolution.